Generalities about Alkane Metathesis Reaction

In the presence of an acyclic alkane, 3 catalyzes at moderate temperature (25-200 °C) the metathesis reaction, leading to the formation of heavier and lower homolog alkanes by simultaneous breaking and formation of C-H and C-C bonds. For example, propane is transformed, even at 25 °C into a quasi-equimolar mixture of ethane and butanes (n- and iso-mixture) as well as methane and pentanes, in lower quantities. Lower and heavier homologs are also obtained starting from 

Alkane metathesis can be described by the following general equation  

Consequently, this reaction could be identified with a process where an alkyl fragment is transferred from one alkane molecule to another. The methyl group is the smallest alkyl fragment and the easiest to be transferred. However, crossmetathesis shows that ethyl and propyl groups can also be transferred. Indeed, heavier homolog alkanes can result from successive reactions or from heavier alkyl group transfer. Consequently, because of the successive reactions, the real product distribution corresponds to the following equation  

---